This application is being filed concurrently with application Ser. Nos. 09/903,112, entitled xe2x80x9cDistal Catheter Assembly With Proximal Mounting Member,xe2x80x9d and 09/903,111, entitled xe2x80x9cTwo-Piece Distal Catheter Assembly,xe2x80x9d both of which are expressly incorporated herein by reference.
The present invention generally relates to medical devices, and more particularly, to methods of assembling catheter tips with sensors.
Catheters are widely used in the medical arts. For example, catheters are sometimes inserted into a patient""s body during mapping and ablation procedures of the patient""s heart. Catheters used for such procedures typically comprise of electrode tips and electrode rings. Various other components may also be incorporated into these medical catheters. For example, a steering mechanism allowing the physician to control the movement of the catheter while the catheter is in a patient""s body may be incorporated into the catheter. A thermistor or a thermocouple may also be placed at the catheter tip to provide temperature data. In addition, such catheters may incorporate other sensors at the tip to assist the physician in performing these delicate procedures.
One type of sensor currently being incorporated into catheter tips is an electromagnetic sensor, which provides important information to the physician about the exact location of the catheter tip relative to the patient""s body. An electromagnetic sensor used for such purposes and commercially available is a xe2x80x9c3Dxe2x80x9d sensor, which employs an orthogonal arrangement of three sensor pairs to provide three-dimensional position coordinates of the catheter tip. Details on the structure and use of a xe2x80x9c3Dxe2x80x9d sensor are discussed in PCT publication WO 00/10456, entitled xe2x80x9cIntrabody Navigation System for Medical Applications,xe2x80x9d which is hereby expressly and fully incorporated herein by reference.
Incorporating such sensors into catheter tips during assembly can be difficult. Catheters used in, for example RF ablation and mapping procedures, tend to be very small in size, thus requiring assembly techniques that must be precise. In addition, electromagnetic sensors are highly sensitive to excess thermal energy and magnetic fields. Even short exposure to excess thermal energy and magnetic fields may cause damage to these sensors. Thus, the assembly of distal catheter assemblies that contain electromagnetic sensors are further constrained, since certain heat generating steps, for example soldering, may potentially expose these sensors to excess heat. Further, many of the components incorporated into these devices are made from ferrous material, such as stainless steel, which can magnetically affect the sensors. Thus, a method for assembling a distal catheter assembly without damaging a magnetic and heat-sensitive component contained therein would be highly desirable.
The present inventions include distal catheter assemblies, catheters, and methods that minimize damage to sensitive components.
In accordance with a first aspect of the present inventions, a distal catheter assembly comprises a composite housing having a cavity formed therein. The composite housing comprises first and second complementary lateral housing sections, i.e., the lateral sides of the housing sections fit together in a complementary fashion. The housing sections are affixed to each other in a suitable manner, e.g., in a pin and hole arrangement. By way of non-limiting example, the housing can include a cap-shaped head and a cylindrical neck. In this case, the head may form an ablation electrode, and ring electrodes, such as mapping electrodes, may be disposed around the neck. A channel may be formed distal to the cavity, where a thermistor can be disposed. Either or both of the head and neck can be formed by the complementary housing sections.
The distal catheter assembly further comprises a component, such as a sensor, mounted within the cavity. The distal catheter assembly may optionally include a second component mounted in the cavity proximal to the first component. The second component can be, e.g., a steering assembly, and if the housing comprises an ablation electrode, an RF lead.
In accordance with a second aspect of the present inventions, a method for assembling a distal catheter assembly comprises mounting a component within a first lateral housing section, and affixing a complementary second lateral housing section to the first housing section subsequent to mounting the component. After mounting the component, the housing sections are affixed to each other in a suitable manner, e.g., in a pin and hole arrangement, to form a composite housing. By way of non-limiting example, the housing can form an ablation electrode, in which case, the housing can include a channel, where a thermistor can be optionally mounted therein.
Optionally, a second component can be mounted within the first housing section by suitable means, e.g., heat generation, and more specifically, soldering. The second component can be, e.g., a steering assembly, and if the housing comprises an ablation electrode, an RF lead. The openness of the first lateral housing section allows the components to be mounted in any order. Preferably, the second housing section is affixed to the first housing section subsequent to mounting the second component. In this manner, the second component can be more easily mounted within a housing. The first component is preferably mounted to the first housing section subsequent to the second component. In this manner, any adverse effects on the first component that would otherwise result from mounting the first component prior to mounting the second component can be minimized or completely eliminated.